The present invention relates to hydraulic control devices particularly, but not solely, for use with mining apparatus, such as displaceable roof supports.
In the mining field, it is known to provide a number of individual control valves in a common block or housing and to actuate the valves when desired by means of a manually-operated lever outside the housing. Usually, the housing is located in an accessible position on or in the vicinity of the apparatus being controlled. The lever is moved by an operator to rotate a cam shaft in the housing which acts with its cam to displace tappets of selected valves to thereby connect hydraulic working chambers of the apparatus to hydraulic pressure fluid feed and return lines in a desired manner. Examples of known devices of this type are described in German Pat. Nos. 2605758 and 1550439. It is also known to utilize devices employing rotary slide valves operated by hand levers to control mining apparatus, such as that described in German Pat. No. 2049869.
A general object of the present invention is to provide an improved hydraulic control device.